Well I'm not battling with it, I haven't battled with anything, I don't really have anything to battle 1000cp Pokémon. And I'm not really interested in battling in Pokémon Go.
I'm mostly just raising their cp for fun. Though candies only give you like 20cp for Butterfree and Beedrill.
Right now my main goal is to get my favorite Pokémon Ninetales and Vileplume but I'm catching whatever to fill up the Pokedex.
Funny you say that. Used to, my strongest PKMN was a Snorlax with 819cp and I fought a gym with two PKMN with cp over 1,000 as well as some lower levels. I lost some PKMN, but I still won with only three PKMN. Battling comes down to more than just CP.